ROCK PHOSPHATES.

Manawatu Standard, Volume LVII, Issue 216, 12 August 1937, Page 5

ROCK PHOSPHATES.

NEED FOR RESEARCH.

; The need for more critical research into the uses of rock phosphates in New Zealand was emphasised by Messrs A. W Hudson, of Massey Agricultural College, and J. \Y. Woodcock, of tlie Department cf Agriculture, in the coulee of a paper given before the animal conference of llie Now Zealand Grassland Association at Dunedin yesterday.

“It is a matter for regret Hint, in yiev. of tlie importance of plio'pbafie fertilise]* to New Zealand, no .serious attempt ha' yet. been made to carry cut a thorough and critical study of the long -range effect' of pliosphatic fertilisers on production and their fate in and effect on the ’soil,” they stated. “An average soil contains .about 30001 b of phosphoric acid in the top 8 o'9 inches. In the course of 50 years annua! applications of about 160. b of Nauru phosphate or 3001 b of superphosphate will add a further 30001 b. In districts whore such quantities arc being regularly applied only a fraction is being removed in crops or by stock. Wliafc of the balance? For how long will sp£h applications be necessary and remunerative? What, in tlie long run, is the best, form in which to apply our phosphate ? These are some of the questions with which we arc already faefcd. and it is certain that the answers to these, which at present cannot be given, will bo much more pressing in another £0 years. “The only mean 3 whereby such questions can be answered lies in the establishment of absolutely permanent experiments under different conditions of soil and climate. Such data as is at present available in this country is provided by experiments of short duration only. The weight of such, evidence favours the useof readily available phosphates. Long-term investigations may emphasise their value still, further, but one must not lose sight, of the possibility that other forms of phosphate may prove more desirable over a long period of years. Tile point is that wo do not know, and it is necessary that we should . obtain the information.”